Top down frac sleeve, method and system

ABSTRACT

A frac assembly including a housing, a port defined radially through the housing, a sleeve disposed in the housing, a self-displacing seat disposed on the sleeve, and a biasing member disposed between the sleeve and the housing. A method for fracturing a wellbore including dropping an object into the wellbore, landing the object on a frac assembly in the wellbore, pressuring the wellbore, reclosing a sleeve of the frac assembly.

BACKGROUND

In the resource recovery and sequestration industry fracturing has become an invaluable and essential treatment for wellbore systems to enhance production or enhance fluid sequestration. Frequently, it is desirable to fracture several stages in the wellbore. Traditionally, this is accomplished from the bottom up and uses differently sized frac objects to land on differently sized frac seats. Since there are a limited number of object sizes between a smallest reasonable seat size and the largest object that will pass a drift diameter of the wellbore, only so many stages are possible. The art would well receive new technologies that increase the number of stages possible and/or increase wellbore efficiency

SUMMARY

An embodiment of a frac assembly including a housing, a port defined radially through the housing, a sleeve disposed in the housing, a self-displacing seat disposed on the sleeve, and a biasing member disposed between the sleeve and the housing.

A method for fracturing a wellbore including dropping an object into the wellbore, landing the object on a frac assembly in the wellbore, pressuring the wellbore, reclosing a sleeve of the frac assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike:

FIG. 1 is a cross sectional representation of a frac sleeve as disclosed herein in a deployment position;

FIG. 2 is the frac sleeve of FIG. 1 in a fracture position;

FIG. 3 is the frac sleeve of FIG. 1 in a reclosed position; and

FIG. 4 is a schematic view of a wellbore system including a frac assembly as disclosed herein.

DETAILED DESCRIPTION

A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures.

This is a top down fracturing system using the same object all the way to the toe of the well, if desired, and with an unlimited number of stages addressable when building the system using the frac assembly as disclosed herein.

Referring to FIG. 1, a frac assembly 10 is illustrated. The term “frac” used herein is used colloquially to refer to “fracture”. This will be recognized by those of skill in the art. The assembly 10 comprises a housing 12 defining a port 14 extending radially through the housing 12. Housing 12 further includes a recess 16 for purpose to be discussed hereunder. A sleeve 18 is slidably disposed within the housing 12 and initially retained there by a release configuration 20, that may be in some embodiments, a shear screw. In the initially retained position, which is the deployment position, the sleeve 18 is disposed over the port 14 to close the port 14. Seals 22 on sleeve 18 and disposed between sleeve 18 and housing 12, straddle the port 14 in the deployment position. The sleeve 18 is biased leftwardly in the drawing by a biaser 24, which is some embodiments is a compression spring. The bias is present in the deployment position but the release configuration prevents movement of the sleeve 18 to the left in the figure.

At an end of the sleeve 18 is a self-displacing seat 26. Seat 26 has two important positions. First is a position where an inside dimension of the seat 26, made up of a plurality of individual segments 28, is capable of retaining an object 30 (Shown in FIG. 2). The seat 26 is maintained in that position because a diameter of a bore 32 of the housing 12 in which the seat 26 is situated permits no radial expansion of the seat 26. Second is a position wherein a resultant inside dimension of the seat 26 is larger than that same object.

In the first seat position, the seat 26 retains the object 30 and provides a seal against which pressure may be applied from surface. The pressure from surface will load the seat 26, the sleeve 18, and the release configuration 20 until that release configuration 20 is overcome and the sleeve 18, seat 26, and object 30 move downhole while simultaneously further compressing biaser 24. The port 14 will also be uncovered in this process and hence be open to ID pressure for fracturing purposes. This assembly position is seen in FIG. 2, The assembly position shown in FIG. 2 is maintained as long as pressure from surface is maintained at a level higher than the spring force provided by the biaser 24 in the opposing direction on sleeve 18. When the fracturing operation is concluded and pressure is bled off, the biaser 24 will overcome the tubing pressure and push the sleeve 18 into a reclosed position. This assembly position is illustrated in FIG. 3. It will be easily appreciated that the sleeve 18 is again covering the port 14 but it is to be noted that seat 26 has moved radially outwardly into recess 16 of housing 12. This is the second position of the seat 26. Radial growth of the inside dimension of the seat 26 allows object 30 (and subsequent objects 30) to pass through seat 26 and travel in the downhole direction to the next adjacent frac assembly 10. In addition, in some embodiments, it is contemplated that the seal 26 in the second position could also function to lock the sleeve 18 in the reclosed position since the outside dimension of the seat 26 is now larger than a bore 32 of the housing.

Enabling the seat to behave in the way just described are radially directed grooves 34 extending radially at one end of the sleeve 18 as shown. In an embodiment, these may be dovetail grooves but any geometry is possible providing movement radially of the segments is enabled. Retention of the segments as well is a benefit of certain geometries such as dovetail. In an embodiment, the seat 26 is movable from the first position to the second position simply by becoming unsupported by bore 32 and the impetus of the object seated thereon, or by becoming unsupported and simply falling open under the influence of gravity on a low side of the seat. If gravity is the only influence, only some of the segments 28 will move to the second position (those that can move radially outwardly under the influence of gravity) while some segments will happen to be positioned relative to gravity such that they will simply stay in the first position. In another embodiment, a spring or springs may be added to the seat 26. Possible spring configurations include compression springs between segments 28 in a circumferential pattern in a somewhat smaller circumference than what outside surfaces of the segments 28 would dictate, a spring ring at the ID of the seat, etc.

Referring to FIG. 4, a wellbore system 40 is illustrated. The system 40 includes a borehole 42 in a subsurface formation 44. A string 46 is disposed within the borehole 42 and one or more of the assemblies 10 are disposed with the string.

Set forth below are some embodiments of the foregoing disclosure:

Embodiment 1: A frac assembly including a housing, a port defined radially through the housing, a sleeve disposed in the housing, a self-displacing seat disposed on the sleeve, and a biasing member disposed between the sleeve and the housing.

Embodiment 2: The frac assembly as in any prior embodiment, wherein the housing includes recess of sufficient dimension to allow the self-displacing seat to achieve an inside diameter larger than an object to be seated on the self-displacing seat when the self-displacing seat is in an object retention position.

Embodiment 3: The frac assembly as in any prior embodiment, wherein the self-displacing seat comprises a plurality of segments.

Embodiment 4: The frac assembly as in any prior embodiment, wherein the segments are movable radially.

Embodiment 5: The frac assembly as in any prior embodiment, wherein the segments are movable radially by impetus of an object seated thereon.

Embodiment 6: The frac assembly as in any prior embodiment, wherein the segments are moved radially by impetus of a spring.

Embodiment 7: The frac assembly as in any prior embodiment, wherein the segments are movable radially outwardly.

Embodiment 8: The frac assembly as in any prior embodiment, wherein the self-displacing seat locks the sleeve in a reclosed position.

Embodiment 9: The frac assembly as in any prior embodiment, wherein the biasing member biases the sleeve to a closed position.

Embodiment 10: A method for fracturing a wellbore including dropping an object into the wellbore, landing the object on a frac assembly in the wellbore, pressuring the wellbore, reclosing a sleeve of the frac assembly.

Embodiment 11: The method as in any prior embodiment further including locking the sleeve in the reclosed position with a self-displacing seat on the sleeve.

Embodiment 12: The method as in any prior embodiment further comprising releasing the object from the seat when the seat moves to the locking position.

Embodiment 13: The method as in any prior embodiment further comprising moving the same object to a next adjacent frac assembly and landing the object on the next adjacent frac assembly.

Embodiment 14: The method as in any prior embodiment, wherein landing the object includes releasing a release configuration and opening the sleeve.

Embodiment 15: The method as in any prior embodiment, wherein the reclosing is by biasing spring.

Embodiment 16: The method as in any prior embodiment, wherein locking the sleeve is by radially outwardly displacing a plurality of seat segments into a recess in a housing.

Embodiment 17: The method as in any prior embodiment, wherein the displacing is to an extent that an inside dimension of the seat is larger than the object.

Embodiment 18: A wellbore system including a borehole in a subsurface formation, a string in the borehole, and a frac assembly as in any prior embodiment disposed with the string.

Embodiment 19: The system as in any prior embodiment, wherein the frac assembly is a plurality of frac assemblies all responsive to the same object.

The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Further, it should be noted that the terms “first,” “second,” and the like herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The terms “about”, “substantially” and “generally” are intended to include the degree of error associated with measurement of the particular quantity based upon the equipment available at the time of filing the application. For example, “about” and/or “substantially” and/or “generally” can include a range of ±8% or 5%, or 2% of a given value.

The teachings of the present disclosure may be used in a variety of well operations. These operations may involve using one or more treatment agents to treat a formation, the fluids resident in a formation, a wellbore, and/or equipment in the wellbore, such as production tubing. The treatment agents may be in the form of liquids, gases, solids, semi-solids, and mixtures thereof. Illustrative treatment agents include, but are not limited to, fracturing fluids, acids, steam, water, brine, anti-corrosion agents, cement, permeability modifiers, drilling muds, emulsifiers, demulsifiers, tracers, flow improvers etc. Illustrative well operations include, but are not limited to, hydraulic fracturing, stimulation, tracer injection, cleaning, acidizing, steam injection, water flooding, cementing, etc.

While the invention has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims. Also, in the drawings and the description, there have been disclosed exemplary embodiments of the invention and, although specific terms may have been employed, they are unless otherwise stated used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention therefore not being so limited. 

What is claimed is:
 1. A frac assembly comprising: a housing; a port defined radially through the housing; a sleeve disposed in the housing; a self-displacing seat disposed on the sleeve; and a biasing member disposed between the sleeve and the housing.
 2. The frac assembly as claimed in claim 1 wherein the housing includes recess of sufficient dimension to allow the self-displacing seat to achieve an inside diameter larger than an object to be seated on the self-displacing seat when the self-displacing seat is in an object retention position.
 3. The frac assembly as claimed in claim 1 wherein the self-displacing seat comprises a plurality of segments.
 4. The frac assembly as claimed in claim 1 wherein the segments are movable radially.
 5. The frac assembly as claimed in claim 4 wherein the segments are movable radially by impetus of an object seated thereon.
 6. The frac assembly as claimed in claim 4 wherein the segments are moved radially by impetus of a spring.
 7. The frac assembly as claimed in claim 1 wherein the segments are movable radially outwardly.
 8. The frac assembly as claimed in claim 1 wherein the self-displacing seat locks the sleeve in a reclosed position.
 9. The frac assembly as claimed in claim 1 wherein the biasing member biases the sleeve to a closed position.
 10. A method for fracturing a wellbore comprising: dropping an object into the wellbore; landing the object on a frac assembly in the wellbore; pressuring the wellbore; reclosing a sleeve of the frac assembly.
 11. The method as claimed in claim 10 further including: locking the sleeve in the reclosed position with a self-displacing seat on the sleeve.
 12. The method as claimed in claim 11 further comprising releasing the object from the seat when the seat moves to the locking position.
 13. The method as claimed in claim 12 further comprising moving the same object to a next adjacent frac assembly and landing the object on the next adjacent frac assembly.
 14. The method as claimed in claim 11 wherein landing the object includes releasing a release configuration and opening the sleeve.
 15. The method as claimed in claim 11 wherein the reclosing is by biasing spring.
 16. The method as claimed in claim 11 wherein locking the sleeve is by radially outwardly displacing a plurality of seat segments into a recess in a housing.
 17. The method as claimed in claim 11 wherein the displacing is to an extent that an inside dimension of the seat is larger than the object.
 18. A wellbore system comprising: a borehole in a subsurface formation; a string in the borehole; and a frac assembly as claimed in claim 1 disposed with the string.
 19. The system as claimed in claim 18 wherein the frac assembly is a plurality of frac assemblies all responsive to the same object. 